The lyrics on the Melvins album "Houdini" are almost entirely gibberish, it's mostly English but the words are half random and half nonsense. If you squint your ears a bit, you can imagine what it's like to have brain damage. Classic! Looks like the whole album is on yourube, check out some examples...
As a bilingual speaker with a love for linguistics, this thought often crosses my mind. The broader question is, when does a foreign language stop sounding foreign?
I taught myself many languages and I can definitely recognize a point where I no longer feel like I'm just making sounds, but speaking actual words. It is true in the other direction as well when it comes to listening. It doesn't take years of study or anything remotely close to fluency to cross that bridge. For me, I think it takes two months of immersion for a foreign language to no longer sound foreign. I think unfamiliarity with a particular language's set of pitch, volume and cadence is what makes a language sounds foreign. Once you're familiar with them, it no longer sounds foreign. I may not know the words, but I'm more familiar and comfortable with the cadence, intonation, sound library, pitch, volume, etc of that language.
For example, every language has a particular native pitch. And if you're used to one language, this pitch change might strike you as jarring when hearing a foreign language. For example, my Japanese voice is deeper than my English voice and my Cambodian voice is higher than both of them. When speaking Swedish, my voice drops very deep compared to English.
Because of my meta-awareness of this phenomenon, I can actually "switch" my brain off of English and hear what English sounds like to foreigners.
As an American English speaker, I've always wondered this. I didn't find the video "hilariously funny", but I was smiling; they did a good job. I couldn't pick up any words, but my brain refused to believe there weren't any. It had that right tempo, cadence, patterns, etc. Nicely done.
I should also add that the top youtube comment for this video (a transcription of the bird's conversation) is actually the most useful (perhaps only useful) youtube comment I've come across.
http://www.youtube.com/watch?v=KwSOrd4E7yw (Night Goat) http://www.youtube.com/watch?v=OPkHP3a9WKU (Lizzy)